Controlled hydrocracking



United States Patent Oflice 3,378,482 CONTRQLLED HYDROCRACKING ElliottP. Doane, Bartlesville, 014121., assignor to Phillips Petroleum Company,a corporation of Delaware Continuation-impart of application Ser. No.399,362,

Sept. 25, 1964. This application Sept. 9, 1966, Ser.

3 Claims. (Cl. 208108) ABSTRACT OF THE DISCLOSURE Process and apparatusfor the controlling of distillate to gasoline ratio in the productobtained by the hydrocracking of gas oil wherein the desired ratio ofgasoline to distillate is achieved by utilization of either cocurrent orcountercurrent hydrogen flow.

This application is a continuation-impart of my copending applicationSer. No. 399,362, filed Sept. 25, 1964, now abandoned.

This invention relates to hydrocracking heavy gas oil. Morespecifically, this invention relates to a method and apparatus forcontrolling the hydrocracking of oil so as to obtain and vary asrequired a desired ratio between the gasoline and distillate producedtherefrom.

In conducting an integrated refining operation, it is highly desirableto have a flexible operation which would allow for producing maximumquantities of those products required due to seasonal demand while atthe same time minimizing the production of those products which are notin such demand so as to avoid the expense of storing same. Thus, forexample, in the hydrocracking of oils it would be desirable toseasonably alter the ratio of gasoline to distillate so as to achieve adistillate-to-gasoline ratio in line with consumer demand.

Accordingly, it is an object of the present invention to provide amethod for achieving control of a hydrocracking operation so as to meetseasonal demands for the products therefrom. Another object of thisinvention is to provide a method for achieving control of thedistillateto-gasoline ratio in the hydrocracking of virgin or crackedheavy gas oil.

A still further object of this invention is to provide a hydrocrackingunit having a controlled gasoline-distillate ratio.

A further object of this invention is to provide a method and apparatusfor the control of product ratio in the hydrocracking of heavy gas oil.

Other objects, advantages and features of the invention will be apparentto those skilled in the art from the following description, the drawing,and the appended claims.

In accordance with this invention, Ihave now discovered that the ratioof distillate to gasoline can be controlled during hydrocracking of gasoils or heavy cycle oils boiling above about 600 F. by operating thecracking process with either cocurrent or countercurrent hydrogen flow.The yield of gasoline when using countercu-rrent flow of the hydrogenrelative to the flow ofthe gas oil or heavy cycle oil feed isconsiderably higher that it is with a cocurrent hydrogen flow. In somecases the gasoline yield can be doubled by changing from cocurrent tocountercurrent flow.

By determining the ratio of the output of gasoline and distillateproducts from the hydrocracking unit, the quantity of and path of flowof hydrogen introduced to the hydrocracking unit is regulated responsivethereto so as to produce the desired gasoline and distillate products inany particularly desired ratio. This in turn serves to render theoperation more flexible, thereby overcoming the major 3,378,482 PatentedApr. 16, 1968 Broad Preferred Temperature, F 500-900 550850 Pressure,p.s.i.g 500-5, 000 1, 000-3, 000 Hz, S.e.f./bl)l. 500-12, 000 4, 500-10,000 Gas oil, LHSV 9 0.1-10. 0 0. 2-3. 0

1 Standard cubic feet per barrel. 2 Liquid hourly space velocity.

Any of the hydrocracking catalysts known to the industry can be used inthe process of my invention. For example, the active hydrocrackingingredient can be selected from the Group VI-B (Langes Handbook ofChemistry, eighth edition, pp. 56-57) oxides and sulfides and the GroupVIII metals, oxides and sulfides, or mixtures thereof. Usually a GroupVI-B metal oxide or sulfide is used together with a Group VIII ferrousmetal, oxide or sulfide, Whereas a Group VIII metal, oxide or sulfide isfrequently used alone. Exemplary of active hydrocracking ingredientsthat can be used are nickel, platinum, cobalt, palladium, nickeloxide-molybdenum oxide (frequently referred to as nickel molybdate),iron sulfide nickel, sulfide, cobalt sulfide-molybdenum sulfide, nickeloxide-tungsten oxide (frequently referred to as nickel tungstate),nickel sulfide-tungsten sulfide, tungsten sulfide, and the like. Theactive ingredient, or each of the active ingredients if there is morethan one, can be present (as metal) to the extent of 0.1 to 25.0 Weightpercent, preferably 1.0 to 15.0 weight percent, of the support. Quitefrequently the catalyst is sulfided by treatment with a material such ascar- 'bon disulfide before use. It is also possible to obtain the sameeffect by operating with a sulfiding material in the feed, or by bothpresulfiding and operating with a sulfiding material in the feed.

The invention is described particularly with reference to asilica-alumina support, but any of the known acidic supports can be usedto prepare catalysts for the inventive process. Exemplary of otheracidic supports are silicazirconia, silica-alumina-zirconia,silica-magnesia, silicaalumina-magnesia, silica-thoria,silica-alumina-thoria, alumina-boria and the like. The support used canoptionally be treated with steam to decrease the acidity or with ahalogen or halogen acid to increase the acidity.

A more complete understanding of the invention may be had by referenceto the accompanying schematic flow diagram illustrating one arrangementof apparatus and flow for effecting the desired results of theinvention.

As shown in the accompanying drawing, heavy gas oil or other heavyhydrocarbon feed stock is introduced from a supply source by way ofconduit 2 into upright hydrocracking unit 4 having a conventionalcatalyst bed 6 therein. Outlet 8 is provided to remove liquid productsfrom the hydrocracking unit. Hydrogen from hydrogen storage unit 10 isintroduced by means of conduit 12 and two way motor valve 14 into eitherconduits 16 or 18 and then into either the upper or lower end zone ofthe hydrocracking unit 4. The feed in admixture with hydrogen ishydrocracked in unit 4 to produce gasoline and distillate. Gaseousproducts, including unreacted hydrogen, hydrogen sulfide, ammonia, andthe like, from the hydrocracking unit are removed by means of conduits20 or 22 and two-Way motor valve 24 and thereafter passed by means ofconduit 26 into separation zone 28 from which hydrogen can be optionallyrecycled to storage unit 10. The 'efll-uent removed by means of conduit8 consists essentially of gasoline and distillate products of thehydrocracking reaction. The reaction effluent of gasoline and distillateis passed by means of conduit 8 to distillation unit 30 wherein thegasoline portion is removed by means of conduit 32. Distillate isremoved through conduit 34. Flow transmitter 36 is provided in conduit32 to provide a first signal representative of the rate of flow ofgasoline product from the distillation zone 30. Flow transmitter 38 isprovided in conduit 34 to provide a second signai representative of therate of flow of distillate product from the distillation Zone 30. Firstand second signals produced by fiow transmitters 36 and 38 areintroduced to ratio controller 40 which is preset to a desired ratio ofdistillate to gasoline, and which compares the received signals andissues responsive thereto a third signal representative of thedifference, if any, between the desired ratio and the actual producedratio of distillate to gasoline. Responsive to the thus produced signal,motor valves 14 and 24 are manipulated so that when thedistillate/gasoline ratio produced by the hydrocracking is above thatdesired, generally 1.5 to 1, hydrogen from storage zone is introducedthrough conduit 18 into the lower zone of unit 4 and gaseous productsare withdrawn through conduit 20, thus giving a countercurrent flow ofhydrogen in the hydrocracking unit. Conversely, when the distillate/gasoline ratio is below that desired, valves '14 and 24 are actuated sothat hydrogen from storage zone 10 is introduced through conduit 16 intothe upper zone of unit 4 and gaseous products are withdrawn throughconduit 22, thus giving a cocurrent flow of hydrogen to thehydrocracking unit. By operating in the above manner, sufiicienthydrogen is provided to the hydrocracking unit in either a cocurrent orcountercurrent direction to provide .any desired ratio of distillate togasoline.

The process and apparatus of this invention are particularly suitablefor producing and maintaining a distillate to gasoline ratio value ofeither above or below 1.5 to 1.

The following example Will further illustrate my invention.

EXAMPLE A Gulf Coast 650+F atmospheric gas oil was utilized in a seriesof runs to demonstrate the present invention. The catalyst was a nickelmolybdate prepared by impregnating /8-l1'1Ch pellets of silica-80alumina with sufficient aqueous ammonium molybdate solution to give amolybdenum content of 7.1 weight percent, drying the composite at about220 F., and calcining it at about 900 F., impregnating with sufficientaqueous nickel nitrate solution to give a nickel content of 1.8 weightpercent, drying the composite at about 220 F. and calcining it at about1100 F. The catalyst was reduced and sulfided before use by heating itin nitrogen to 600 F., pressuring to 2000 p.s.i.g. with hydrogen andcontinuing hydrogen flow for 4 hours, and then passing over the catalystnormal hexane containing about 3 weight percent carbon disulfide at 2000p.s.i.g. and 0.5 LHSV for 4 hours. The two modes of operation werecompared at a temperature of 760 F., a pressure of 2000 p.s.i.g., ahydrogen flow of about 6000 standard cubic feet per barrel, and a gasoil liquid hourly space velocity of 0.25. The following results wereobtained:

Ha Flow Cocurrent Countercurrent Yield, wt. percent:

C1-C4 2.0 3. 5 05-350" F. (Gasoline) 12.5 22.5 350-650 F. (Distillate)35.5 24. O Distillate/Gasoline Ratio 2. 8 1. 1

I claim:

1. In a hydrocracking process wherein a gas oil is passed downwardlythrough a bed of supported hydrocracking catalyst in a hydrocrackingzone maintained under hydrocracking conditions in the presence ofhydrogen, an efiiuent is withdrawn from the lower end of saidhydrocracking zone containing a gasoline fraction and a distillatefraction, and wherein the resulting gasoline fraction and distillatefraction are separated and separately recovered as products of theprocess, the improvement which comprises measuring the rate of How ofsaid gasoline fraction and said distillate fraction so as to obtain theratio of the gasoline fraction and distillate fraction produced,thereafter obtaining a signal representative of the difference between apredetermined ratio of distillate to gasoline and the ratio ofdistillate to gasoline being produced in said hydr-ocracking zone andresponsive to said signal alternately and respectively introducing thehydrogen to said hydrocracking zone so that the hydrogen will passupwardly through said hydrocracking catalyst in countercurrent contactwith said gas oil in an amount sufiicient to produce a distillate togasoline ratio of less than 1.5 to 1 in the converted gas oil whilerecovering hydrogen and light gases from the upper portion of thehydro'cracking catalyst bed and introducing the hydrogen to saidhydrocracking zone so that the hydrogen will pass downwardly throughsaid hydrocracking catalyst in cocurrent contact with said gas oil in anamount sufficient to produce a distillate to gasoline ratio of greaterthan 1.5 to 1 in the converted gas oil while recovering hydrogen andlight gases from the lower portion of the hydrocracking catalyst bed.

2. A process according to claim 1 wherein said gas oil boils above 600F., the temperature within said bed is in the range of 500 to 900 F. andthe pressure is in the range of 500 to 5000 p.s.i.g.

3. A hydrocracking unit comprising in combination (a) an elongatedgenerally upright reaction vessel containing a bed of hydrocrackingcatalyst therein;

(b) distillation means to separate gasoline and distillate produced insaid reaction vessel;

(c) first conduit means communicating with a source of gas oil and theupper end of said reaction vessel to introduce gas oil into saidreaction vessel;

((1) second conduit means communicating with the lower end of saidreaction vessel and said distillation means to remove efliuent from thelower end of said reaction vessel and introducing same to saiddistillation means;

(e) a source of hydrogen;

(f) a first two-position valve means adapted to be responsive to asignal from a ratio-controller means;

(g) third conduit means communicating with said source of hydrogen andsaid first two-position valve means;

(h) fourth conduit means communicating with said first two-positionvalve means and the lower end of said reaction vessel;

(i) fifth conduit means communicating with said first two-position valvemeans and the upper end of said reaction vessel;

(j) accumulating means for gaseous effluent from said reactor vessel;

(k) second two-position valve means adapted to be responsive to a signalfrom a ratio-controller means;

(1) sixth conduit means in communication with said second two-positionvalve means .and the lower end of said reaction vessel;

(in) seventh conduit means in communication with said accumulating meansand said source of hydrogen;

(n) eighth conduit means in communication with said second two-positionvalve means and the upper end of said reaction vessel;

(0) ninth conduit means in communication with said second two-positionvalve means and said accumulating means;

said first and second two-position valve means in a first positionconnecting said source of hydrogen to said fifth conduit and saidaccumulating means to said sixth conduit means;

said first and second two-position valve means in a second positionconnecting said source of hydrogen to said fourth conduit means and saidaccumulating means to said eighth conduit means;

(p) tenth conduit means in communication with the upper end of saiddistillation means to remove an overhead efiiuent therefrom;

(q) eleventh conduit means in communication with the lower end of saiddistillation means to remove a distillate effluent therefrom;

(r) twelfth conduit means communicating with the lower end of saiddistillation means and said first conduit means to remove a bottomseffiuent from said distillation means and recycle same to said reactionvessel;

(s) first flow transmitter means positioned in said tenth I conduitmeans so adapted to provide a first signal representative of the rate offlow of gasoline from said distillation means;

(t) second flow transmitter means positioned in said eleventh conduitmeans so adapted to provide a second signal representative of the rateof flow of distillate efiiuent from said distillation means;

(u) ratio controller means adapted to receive said first and secondsignals and to produce a third signal responsive thereto to said firstand second two-position valve means whereby said valve means aremaintained in one of said first and second positions.

References Cited UNITED STATES PATENTS 2,602,771 7/ 19521 Munday et al208-159 3,186,935 6/1965 Vaell 208108 3,234,121 2/1966 MacLaren 2081123,256,176 6/1966 Mills 208112 3,268,438 8/1966 Scott et al 208-89ABRAHAM RIMENS, Primary Examiner.

